The invention relates to a method and an arrangement for controlling the drive unit of a vehicle.
A method and an arrangement of this kind are disclosed in DE-A 195 23 898. There, to reduce vibrations in the drive train of the vehicle, the torque of the drive unit, for example, the ignition angle thereof, is influenced in accordance with a comparison between the rpm of the drive unit and a model or desired rpm obtained based on the torque conditions in the drive train of the vehicle. The model or desired rpm is formed by integration from a torque representing the driver command. By comparing the model or desired rpm to the rpm of the drive unit, vibrations of the vehicle drive are recognized and isolated in order to be then dampened by phase-correct torque interventions. The use of this so-called anti-jolt function leads to unexpected vehicle reactions when a transmission is downshifted when depressing the accelerator pedal. The increase of the engine rpm connected therewith is interpreted as drive train vibration and leads to a reduction of the engine torque. This is perceived by the driver as being unpleasant. This problem occurs primarily in continuously variable transmissions or in transmissions having a continuous shift characteristic but can also be significant in other transmission types.
It is an object of the invention to provide measures which optimize an anti-jolt function even for downshifting operations of a transmission.
With the formation of the desired or model rpm, which is described hereinafter, it is effectively avoided that the reduction of the engine torque occurs as a consequence of the anti-jolt function when depressing the accelerator pedal while downshifting a transmission. The acceleration characteristic of the vehicle is improved.
It is especially advantageous that a deterioration of the anti-jolt function does not take place so that this function displays its usual advantages and effectively suppresses drive train vibrations.
It is especially advantageous that the desired or model rpm is formed on the basis of operating variables which are anyway available. In this way, a reduction of the complexity results with improved function.
The application of the procedure described hereinafter is especially advantageous with continuously variable transmissions. In this application, an especially advantageous effect is achieved and the driving performance of the vehicle is considerably improved when depressing the accelerator pedal.